1. Field of the Invention
The technical field of the present invention relates to a semiconductor device.
2. Description of the Related Art
Patent Document 1 and Patent Document 2 each disclose a semiconductor device including a transistor whose active layer has an oxide semiconductor layer.
The active layer is a semiconductor layer having at least a channel formation region.
The channel formation region is a region in which a channel can be formed.
A paragraph [0010] in Patent Document 1 discloses the following: “impurities such as a compound containing a hydrogen atom typified by H2O, a compound containing an alkali metal, or a compound containing an alkaline earth metal in the deposited oxide semiconductor film increase the carrier density of the oxide semiconductor film”.
A paragraph [0010] in Patent Document 2 discloses the following: “a hydrogen element serves as a carrier (a donor) in an oxide semiconductor layer.”
[Reference]
    [Patent Document 1] Japanese Published Patent Application No. 2012-072493    [Patent Document 2] Japanese Published Patent Application No. 2011-142311